The present invention relates to a dental prophy cup used in dental prophylaxis procedures and, in particular, to a novel configuration and construction of such a cup.
A dental prophylaxis procedure typically involves the application of an abrasive paste (i.e., a paste containing abrasive particles) to a tooth surface upon which pressure and rotational motion are applied. The removal of plaque, calculus and stains is facilitated by the resultant abrasion at the interface between the abrasive particles and tooth surface.
The pressure and rotational motion are applied to the abrasive paste by means of a prophy cup which comprises a flexible cup-shaped element of about one-quarter inch diameter. A rear portion of the cup is mounted on a drive shaft which rotates the cup at high speed, e.g., about 1500 rpm. The front portion of the cup forms an internal cavity which receives the paste. The wall of the cavity typically includes a plurality of fins extending in a front-to-rear direction. An operator presses the front portion of the cup against a tooth following the insertion of abrasive paste into the cavity. The paste serves as a lubricant, and the abrasives in the paste function to abrade away plaque, calculus, and stains from the tooth surfaces.
This procedure has traditionally exhibited certain shortcomings. For example, the centrifugal force generated by a prophy cup rotating at 1500 rpm causes the paste to be displaced from the cavity. In fact, the amount of paste retained at the interface between the cup and tooth surface after one second (25 rotations) is a small fraction of the initial volume. This diminishing of paste results in reduced abrasion and cleaning performance.
An additional shortcoming relates to the geometry of the cup itself. In that regard, prophy cups are designed to be flexible, so that as the operator presses the cup against a tooth surface, the outer annular rim of the cup flexes in order to conform to the shape of the tooth surface, and thereby increase the area of surface contact therebetween. However, the presence of fins along the cavity wall tends to stiffen the cup, so that the ability of the cup to flex and conform to the curvature of the tooth surface is reduced. This makes it difficult for the operator to control the magnitude and placement of abrasion.
Therefore, it would be desirable to provide a dental prophy cup which increases the residence time and degree of distribution of abrasive paste therein.
It would also be desirable to increase the flexibility of the cup to enable the cup to better conform to the shape of the tooth.